Upgrade Miyoo Mini Plus firmware from 202303021817 to latest

[Tojgli]

Hey guys,

I bought an MMP last year, successfully upgraded the firmware from the original (202302181113) to 202303021817, installed onion (I believe 4.2) and used it. Life happened, I moved places, and the MMP was in the bottom of a box for a long time, but now I would like to refresh to the latest again.

As the document is saying, I started with a firmware upgrade, but whatever I do, it just doesn't want to start the upgrade process, always goes directly to the charging screen. I looked through all the similar issues others asked and the potential solutions, but nothing helped.

Just to summarize, I explain what I did:

• I verified that my current firmware is a lower version than the one I am trying to upgrade to
• I tried multiple sd cards. Small, big, good brand, bad one, etc.
• I didn't use the original sd card reader, plugged the sd card directly to a laptop, so most likely it is not corrupted because of that
• Formatted the sd card to fat32, used different cluster sizes
• I tried ALL firmware files from the github page, all behaved completely the same
• I asked chatgpt, which gave me all sort of weird woodoo recommendations, but just to be sure, I went through those as well. This including turning it on before plugging in the cable, turning it on after plugging in the cable, pressing butting while charging, etc
• chatgpt also mentioned that there could be an issue with my current firmware (202303021817) that it will not be able to recognize newer firmware versions and recommended me to roll back before upgrading to the latest version, but the only firmware that has a lower version is the original (202302181113) which I cannot find anywhere. Seems like the stock firmware is not available anywhere - and people also incorrectly referring to the stock OS as the stock firmware, so while I am able to put back the stock OS, that will not downgrade the firmware.
• I tried removing the battery as well for the upgrades, still didn't help
• I tried different cables, different power supplies (wall socket, laptop, PC, etc) as well

So now I am a bit stuck, because I am slowly getting out of options. Just to reiterate - I already upgraded the firmware successfully in the past, but now whatever I do it just brings me to the charging screen. Anyone has any idea what else I could try?

Thanks for the help!